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MEV-001: Introduction to Environmental Health

MEV-001: Introduction to Environmental Health

IGNOU Solved Assignment Solution for 2022-23

If you are looking for MEV-001 IGNOU Solved Assignment solution for the subject Introduction to Environmental Health, you have come to the right place. MEV-001 solution on this page applies to 2022-23 session students studying in PGDEOH, MAEOH, PGDINDS courses of IGNOU.

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Assignment Code: MEV-001/ASST/TMA-01/2022-23

Course Code: MEV-001


Year: 2022-2023

Verification Status: Verified by Professor


Maximum Marks 100


Attempt any five questions. All questions carry equal marks. 5x20=100


1. What are the human dimensions of global environmental changes and explain about environmental sustainability?

Ans) Most of the changes in the global environment today can be traced back to human actions. Human actions have had such a big impact on the Earth's system that the current era is called the "Anthropocene." Human activity keeps getting much more intense, which puts more pressure on the Earth's resources and, for example, on its ability to absorb waste. Rapid population growth and overpopulation affect the environment, the economy, and society in many ways. The growing number of people on Earth is putting more stress on its natural resources and environment. People moving to cities means that more people will have access to health care, education, and other services. This means that people's living standards are likely to get better. More places will be able to take advantage of economies of scale if they have a higher population density.


Carrying Capacity

In ecology, carrying capacity is usually defined as the maximum number of a certain species that can live indefinitely in a certain habitat without permanently affecting the number of people who can live there. In terms of physical resources, our planet is almost like a closed system, and everything we do depends on these limited resources. The idea of "carrying capacity" is important and should be the most important thing we think about when planning for the future. This is because the world's population is growing and our exploration for food is quickly destroying natural ecosystems. The Club of Rome has warned us about what could happen if the world's population keeps growing and industrialization keeps going.


Loss of Ecosystem Services

The Millennium Ecosystem Assessment 2001 says that "ecosystem services are the benefits that people get from ecosystems" and divides services into four groups. Provisioning services provide goods for direct human use, like food, fresh water, wood, and fibre. Regulating services keeps the world biophysically safe for people to live in and gives people benefits like crop pollination, less water damage, and a more stable climate. Cultural services make the world a place where people want to live. They include entertainment as well as things that inspire people on an intellectual, spiritual, and aesthetic level.

Environment and Health

Human health and well-being depend on living in a clean and healthy environment. Air and water pollution, as well as dirty living conditions, often have negative effects on health. Changes in the global environment, such as climate change, the loss of biodiversity, and the depletion of stratospheric ozone, could have an effect on human health. Air pollution can cause problems with your lungs, heart, and blood vessels, as well as asthma, allergies, and other conditions. Since the connections between the environment and human health are complicated, most people agree that the precautionary principle should be used.


Environmental Sustainability

The ability to last is called sustainability. In ecology, this word refers to how living things stay different and productive over time. For people, it is the possibility of long-term well-being, which depends on keeping the natural world and natural resources in good shape. Sustainability has become a broad term that can be used to talk about almost every part of life on Earth, from the local to the global level and over different lengths of time. Sustainability is defined as the need for our generation to manage the resource base in a way that makes it possible for all future generations to have the same average quality of life that we have.

2. Explain the causes of environmental degradation & how human health is affected by this?


Natural Causes

Instability in the environment is caused by both human and natural factors. Events like earthquakes, floods, wildfires, and landslides can hurt people and damage property, as well as change the way the landscape looks. Changing the environment makes it hard for the plant and animal communities to stay alive. This is because the climate of Earth has also been changing over time.


Man –made causes

Compared to natural causes, human causes are known to have a much bigger effect on the environment. Some of the most important things that people do to hurt the environment are deforestation, pollution, bad land use planning and development, overuse of natural resources, bad farming methods, poor water quality, destruction of wetlands and aquatic life, and making a lot of trash. From 1960 to 1999, the world's population grew by a factor of ten because we had better medical care, more vaccinations, better food, and deadly diseases were under control. rate dropped by a lot during this time.


During the same time, environmental problems got worse, and the world started to pay more attention to those problems. All of the important environmental events happened during the same time frame. Since then, the problems with the environment have grown worse and more complicated. In the name of development, people have changed the environment and natural processes. Unless strict steps are taken, it will be hard to get forests, oceans, and other ecosystems back to how they used to be.


The degradation of the environment makes it harder for natural resources to grow back, which limits their availability. It also makes the land, water, genetic resources, medicinal plants, and food crops less useful. Here are some of the most important things that happen when the environment gets worse. In later units of this course, you will learn more about what happens when the environment gets worse.


Atmospheric Changes

Biogeochemical cycles and other natural processes are upset by damage to the environment. Careless cutting down of trees and mining damage the natural land cover and change the chemical makeup of the air. It makes problems like global warming and the release of greenhouse gases even worse than they already are. Along with this, natural disasters are getting worse and happening more often. Overall, the result is a change in the way rain and snow fall, as well as changes in the atmosphere.


Environmental Pollution

Harmful and unwanted chemicals get into the environment because the environment is getting worse. Rapid industrialization and unplanned growth have hurt more than they have helped. Our farms are slowly poisoning our fields, and pesticides are getting into our fruits and vegetables. The air is also getting dirty, and our water is full of trash and chemicals that are bad for us. There are piles of solid and municipal waste in places that are hard to reach, which pollutes the land. In a nutshell, pollution has gone too far and is one of the most obvious ways that the environment is getting worse.


Decline in Biodiversity

The destruction of forests and natural ecosystems has been caused by the damage to the environment. The number of threatened species around the world keeps going up, and many of them have already died out. This is because the water bodies are getting more acidic, trees are being cut down, and natural habitats of living things are being destroyed on purpose.

3. What is meant by atmospheric effect and the reactions that occur in the atmosphere?

Ans) People think of the atmosphere as the smallest geological reservoir on Earth. The natural atmosphere is made up of three open systems: the biosphere, the lithosphere, and the hydrosphere. The troposphere is the lowest layer of the atmosphere.


Above it is the stratosphere, and above that are two more layers: the mesosphere and the thermosphere. All of the layers are separated by things like the tropopause, the stratopause, and so on. Because the atmosphere mixes so much, the parts of the atmosphere are pretty much the same everywhere on Earth. But some weather factors keep changing because conditions are always changing. Atmospheric effects are the changes in temperature, air, pressure, wind, humidity, and rain that happen every day. By knowing about these effects, we can easily predict the changes caused by people, so they are very important.


Reactions in Atmosphere

In the troposphere, most of the chemical reactions that happen in the air take place. Due to chemical reactions, the chemical composition of the atmosphere became out of balance. This led to the redistribution of chemical species, which lowered the temperature of the atmosphere. The troposphere of the atmosphere is made up of water vapour and a mix of important gases like O2, N2, CO2, etc. It is in charge of regulating and directing the flow of energy to the earth, which in turn affects the biogeochemical cycle of gases, water vapours, etc. The troposphere is also called the "turning sphere" because convection keeps it well mixed. Most of the time, the gases are stable, but when some things change, they react to make new compounds.


The sun's rays start the chemical reactions in this part of the atmosphere. The sun sends out radiation with a wide range of energies. In this case, we are interested in visible light, which human eyes can see, and UV light, which human eyes can't see and has a higher energy than visible light. The sun's energy warms the earth, which in turn warms the air above it. This is called convective mixing. Because hot air tends to rise, this is what happens. As the air rises, it creates areas of high pressure in the sky and low pressure near the ground. High-pressure air that is rising is cooled by heat radiation, which makes it rain. Then the air moves sideways. Because of this difference, winds happen. Some way or another, all of the gases get into the air. This could come from either natural or human-made sources on the surface of the earth. Along with these gases, there are also some species that have an electric charge. Most of these species that live in the troposphere can get rid of oxygen.


Aqueous H2O2 comes from the breakdown of gaseous H2O2 into water droplets in the air. The other sources are organic compounds breaking down superoxide, hydrogen carbonate, light breaking down ozone in water, and water vapour photo nucleation. In the aqueous phase, the photo nucleation is mostly caused by the oxidation of S(IV) to S(VI). This is a major source of the sulphate particles that act as cloud condensation nuclei and are a key part of how acidic aerosols and acid rain are made.


4. Explain various types of water pollutants, their sources, and effects?

Ans) Water pollution is when water bodies get dirty, usually because of things people do, in a way that makes them less useful. Lakes, rivers, oceans, aquifers, reservoirs, and groundwater are all types of water bodies. When contaminants get into these water bodies, they pollute the water. There are four things that can pollute water: sewage discharges, industrial activities, farming activities, and urban runoff, which includes stormwater. It can be put into two groups: water pollution on the surface and water pollution in the ground. For example, putting wastewater that hasn't been treated well enough into natural waters can hurt these ecosystems. People who drink, bathe, wash, or water their crops with polluted water can also get diseases that spread through water. When pollution gets into a body of water, it makes it less able to do the things it would normally do for the ecosystem.


Point sources and non-point sources are both ways that water gets dirty. A storm drain, a wastewater treatment plant, or an oil spill are all examples of point sources. Non-point sources are more spread out, like runoff from farms. Pollution is caused by small changes that add up over time. Pollution can come in the form of toxic substances (like oil, metals, plastics, pesticides, persistent organic pollutants, and industrial waste), stressful conditions (like changes in pH, hypoxia or anoxia, higher temperatures, too much turbidity, a bad taste or smell, and changes in salinity), or pathogenic organisms. Both organic and inorganic substances can be contaminants. Thermal pollution is the term for when heat is a pollutant. Power plants and factories that use water as a coolant are a common source of thermal pollution.


In addition to laws, the right infrastructure and management plans are needed to stop water pollution. Improvements in sanitation, sewage treatment, industrial wastewater treatment, agricultural wastewater treatment, erosion control, sediment control, and urban runoff control can be made with technology (including stormwater management). Getting rid of urban runoff means slowing it down and making it flow less.



  1. Sewage: Emptying the drains and sewers in freshwater bodies causes water pollution. The problem is severe in cities.

  2. Industrial Effluents: Water pollution comes from things like toxic chemicals in industrial waste, acids, alkalis, metallic salts, phenols, cyanides, ammonia, radioactive materials, and so on. They also make water dirty by adding heat to it.

  3. Synthetic Detergents: Synthetic detergents used in washing and cleaning produce foam and pollute water.

  4. Agrochemicals: Agrochemicals like fertilisers (with nitrates and phosphates) and pesticides (insecticides, fungicides, herbicides, etc.) that get washed off by rainwater and surface runoff pollute water.



  1. Disorders: Some pollutants like sodium can cause cardiovascular diseases, while mercury and lead cause nervous disorders.

  2. Toxic Substances: DDT is a poison that can change the way chromosomes look. Some of these chemicals, like pesticides, methyl mercury, and so on, get into the bodies of living things because they are in the environment where they live. These substances tend to build up in the body of an organism because of the food it eats. Bioaccumulation or bioconcentration is the name for this process. At each level of the food chain, the amount of these harmful chemicals gets higher. Bio magnifications is the name for this process.


Water Pollution

Fluoride pollution leads to a disease called fluorosis, which affects teeth and bones. Arsenic, on the other hand, can do a lot of damage to the liver and nervous system. In addition to all of this, the organic compounds in polluted water help algae and other weeds grow, which uses up more of the oxygen in the water. This cuts down on the amount of oxygen that can dissolve in the water, leaving less oxygen for fish and other aquatic life.


5. How the agriculture, industrial, urban, and nuclear waste can contribute to the soil pollution?

Ans) Soil pollution is a big problem all over the world because of the past 200 years of industrialization. Pollution can hurt people's health, and most people, including decision makers, scientists, businesses, and regular citizens, know and agree with this. However, the effects of soil pollution on our health are not well known. The main things that pollute soil are mining and quarrying, household trash, waste from the construction industry, biomedical waste, agricultural waste, and so on. These wastes get into the groundwater, rivers, lakes, and streams through rain, irrigation, and drainage. This pollutes the water and throws off the natural balance of ecosystems.


Agricultural Sources

In modern agriculture, it is common to use different agrochemicals. There are a lot of different pesticides now, almost 450 different compounds. Herbicides, insecticides, and fungicides are the most common ones, but there are also nematicides, miticides, rodenticides, and molluscicides. Pesticides that are put on seeds or leaves have different effects depending on how they are used, but they all end up in the soil. Pesticide residues that build up in the biosphere cause ecological stress, which pollutes the soil, water, and food. At the end of the 19th century, farmers started using man-made fertilisers, which made it possible to farm more land. Making these fertilisers takes a lot of energy and uses up phosphate ores that could be used for other things.


Industrial Sources

Industrial waste that is dumped without being cleaned or only partially cleaned is a major cause of soil pollution. Some of the main sources of industrial soil pollution are gaseous and solid air pollutants that fall to the ground from mining and smelting operations, smokestacks, and other places. They can come from the textile, leather, chemical, electroplating, glass, distillery, paper, oil, cement, pharmaceutical, and other industries. These wastes are made up of both inorganic and organic materials that change the way our soils are made.


Toxic chemicals that get into the soil could cause a lot of birth defects, cancers, and diseases of the lungs, nervous system, and kidneys. Metalliferous wastes, which contain heavy metals like mercury, lead, zinc, cadmium, copper, and nickel, are often found in soils where ore has been mined or smelted. More metal pollution can also happen on land or soil that is used to sell scrap metal or make ammunition. All metals with an atomic number greater than 23 are heavy metals (with a few exceptions). The metals are called "heavy metals" because in their normal state, their specific gravity is greater than 5 g/cm3. There are sixty heavy metals that are known.


Urban Sources

Every year, tonnes of untreated trash from cities are made. This is bad for people's health, pollutes the soil, and makes it less fertile and productive. Plastics make up a big part of both household and industrial waste around the world. Plastics don't break down in the environment, so they stay there for a long time. Most municipal waste is made up of trash from homes and kitchens, as well as trash from markets, hospitals, slaughterhouses, farms, and other places. Most of the time, people dump their trash on the ground, which is a very big problem. Garbage, food waste, paper, glass, plastics, clothes, metal cans, etc. are all examples of these wastes. These don't break down easily and are bad for the soil. There are organic materials, chemicals, metal needles, plastic and glass bottles, vials, and other things in hospital waste. Pathogens that can be dangerous to human health are spread into the environment when people dump household and hospital waste. Plastics are a big part of both household and industrial waste around the world. They don't break down, so they stay in the soil and add to pollution.


Nuclear waste sources

They are often released into the soil by nuclear explosions, nuclear dust that gets into the air, radioactive labs, and other places. Uranium, Thorium, Radium, and Cesium are all elements that are found in nature and keep giving off radiations for a long time. It is known that they build up in plants. Radiation can get into people's bodies when they eat plants and food that contain it. This can cause mutations and genetic disorders.

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